Honda: Dashcam support for Accord 9G - serial steering

[mvl-boston]

Part of a series of PRs to support serial steering cars in dashcam mode. These cars use linbus for steering and thus require a community translation board to convert canbus signals to linbus for the car to understand.

In total, this series would allow dashcam support for 1.2 million additional cars per North American sales statistics.

This PR supports:

• 16-17 Accord (ACCORD_9G)

Other PRs will support (pending route logs to open):

• 14-17 MDX (ACURA_MDX_3G)
• 18-20 MDX (ACURA_MDX_3G_MMR - different dbc / newer steer status)
• 15-20 TLX (ACURA_TLX_1G)

Note: Hybrid versions of the Accord and MDX additionally require #2671, which is baselined into this PR.

Notes:

• Used legacy pid, because torque controller did not drive as well.
• Created new steering control d. steering control c reserved for Singapore Odyssey

[jyoung8607]

You can put these in the car port directly. Look at the Toyota SecOC cars as an example.

[mvl-boston]

Let me know if this change is correct/complete. Not clear on all the aspects of cardocs.

[adeebshihadeh]

We're not really interested in merging support for cars that don't have a path to being upstreamed.

[jyoung8607]

We're not really interested in merging support for cars that don't have a path to being upstreamed.

Can we reserve judgment on that for now? This PR looks like a Whole Big Thing, but it won't merge that way:

• The diff is mostly Honda - Nidec Hybrid brake control #2671, which will merge first, for supported cars
• Separately, a minor generator refactor to promote the no-longer-snowflake Acura RDX gear message

Once the pre-refactors (prefactors?) are done, the extra carrying-cost of a dashcam-mode serial steering car should be down to a single DBC generator template with a single message in it.

We've told community we'll be more permissive about dashcam merges. Let's take another look once the diff is reduced.

[adeebshihadeh]

I'd like to get to a point where carrying these are free, but we are very much not there, as evidenced by the 144 open pull requests in this repo.

Until we get to that point, I absolutely do not want anything in this repo that makes it harder to get upstream-able cars upstreamed.